ski tow vs surface lift

ski tow and surface lift both are nouns.

Word	Noun	Adjective	Verb	Adverb
ski tow	Yes	No	No	No
surface lift	Yes	No	No	No

As nouns, surface lift is a hyponym of ski tow; that is, surface lift is a word with a more specific, narrower meaning than ski tow:

ski tow: a powered conveyance that carries skiers up a hill
surface lift: a ski tow that pulls skiers up a slope without lifting them off the ground

Other hyponyms of ski tow include chair lift, chairlift, rope tow.

ski tow (noun)	surface lift (noun)
a powered conveyance that carries skiers up a hill	a ski tow that pulls skiers up a slope without lifting them off the ground